I have a 2014 Ford Focus SE. For about 5 weeks, have had error code P07A3 come and go. Have had stuttering come and go when accelerating from stop. Transmission issue. Learned yesterday that my battery was completely dead and unable to hold a charge. That was my bad. Bought the car used and never thought to change out the battery which had been installed for a long time. So I bought and installed a new battery. Since I know a failing battery can cause transmission issues from the transmission not receiving enough battery power, my question is: is it possible the new battery might resolve my transmission error code and stuttering? If so, would it be an immediate fix or would a certain amount of driving have to happen for the fix to take place and the code to disappear?
I don’t know if this is a failing battery.
Ford Focuses from that era had the infamous Ford PowerShift transmission, which were known for failing. I don’t want to hate on your car (you have a very nice little car! 
), but some reviewers told used car buyers to avoid that generation of Ford Focus because of the transmission.
I suggest consulting a Ford dealer about the failing transmission.
Yep, I’m totally aware of the transmission issues with this year of Focus. You’re absolutely right. That said, I’ve had the car about a year and a half and the transmission thing didn’t start for me until 5 weeks ago, right when the battery would have been getting down to its last hours of reserved power. So I couldn’t help but wonder if my particular transmission issues were battery related and not “2014 Focus” related.
I’ll definitely still bring into a transmission shop.
You do that. I’m sure they will be happy to help!
It may take driving the vehicle a while for the TCM to relearn the adaptive memory for the transmission operation.
Tester
Thx so much for that insight. This is what I’d hoped to hear. Because I’m still having a little stuttering but not as severe as I’d been having the last few weeks. Since changing out the battery yesterday, I’ve probably driven 50 miles. Gonna keep my eyes on this.
Examples of how different modules can be affected by loss of battery power:
Door modules Loss of express-up feature due to loss of stored “pinch point”
Engine control module (ECM, PCM, VCM) Loss of learned idle speed which can cause a stalling condition. Resetting of emission monitors can cause a smog inspection failure.
Power seat modules Loss of “learned” seat and mirror positions
Radio Loss of time, radio stations, and possible anti-theft lockout.
Transmission control module Loss of adaptive information; most late module transmissions “learn” how you drive and “learn” to shift accordingly.
Put more miles on the car to see if the transmission starts to behave.
Tester
Yes, all of those are possible. Common sense says to continue to monitor the situation, hopefully the problem will resolve on its own. There’s no way to tell what exactly will happen to a car’s functions if the battery is not up to snuff.
I wonder how a battery dead enough to cause such problems could possibly start the car.
Update: The new battery did indeed clear up my transmission issue. Within a day of installing the battery and putting a certain number of miles on the car, the check engine light went off, the transmission code cleared from my scanner and the stuttering I was feeling is completely gone. The transmission is now getting the proper battery power it needs to work the right way.
Regarding the car starting, I was going on just the charge that was in the battery for the last few weeks without it being recharged. So that’s how the car was able to start. Until this past Sunday when the car finally wouldn’t start at all. The battery has finally become completely drained. Fortunately, I found this out in my driveway at home as opposed to somewhere away from home.
Ur car has an electric fuel pump. You had a bad alternator? Which lead to dead battery? And poor running car? Inconceivable.
No man. My alternator isn’t bad. My battery was bad because it was old and very corroded. Very simple.
Ur alt may seem “good” now but a car elec system does not like to run long with a crappy battery. Maybe you’ll be lucky and have no alt issues.
My basic diy’er alternator/battery test, requires an accurate volt meter: Before first start of the day the battery should measure about 12.6 volts; then immediately after starting engine, 13.5-15.5 volts.